The present invention relates in general to fabrication methods and the resulting semiconductor device structures. More specifically, the present invention relates to fabrication methods and resulting device structures for providing a dual layer shallow trench isolation structure to improve contact patterning margins.
Typical semiconductor devices are formed using active regions of a wafer. The active regions are defined by isolations regions used to separate and electrically isolate adjacent semiconductor devices. For example, in an integrated circuit having a plurality of metal oxide semiconductor field effect transistors (MOSFETs), each MOSFET has a source and a drain that are formed in an active region of a semiconductor layer by implanting N-type or P-type impurities in the layer of semiconductor material. Disposed between the source and the drain is a channel (or body) region. Disposed above the body region is a gate electrode. The gate electrode and the body are spaced apart by a gate dielectric layer.